A wireless communication device, such as a mobile phone device or a smart phone, may include two or more Subscriber Identity Modules (SIMs). Each SIM may correspond to at least one subscription via a Radio Access Technology (RAT). Such a wireless communication device may be a multi-SIM wireless communication device. In a Multi-SIM-Multi-Active (MSMA) wireless communication device, all SIMs may be active at the same time. In a Multi-SIM-Multi-Standby (MSMS) wireless communication device, if any one SIM is active, then the rest of the SIM(s) may be in a standby mode. The RATs may include, but are not limited to, Frequency Division Multiple Access (FDMA), Time Division Multiple Access (TDMA), Code Division Multiple Access (CDMA) (particularly, Evolution-Data Optimized (EVDO)), Universal Mobile Telecommunications Systems (UMTS) (particularly, Wideband Code Division Multiple Access (WCDMA), Long Term Evolution (LTE), High-Speed Downlink Packet Access (HSDPA), and the like), Global System for Mobile Communications (GSM), Code Division Multiple Access 1× Radio Transmission Technology (1×), General Packet Radio Service (GPRS), Wi-Fi, Personal Communications Service (PCS), and other protocols that may be used in a wireless communications network or a data communications network.
A Concurrent RAT (CRAT) wireless communication device refers to a multi-SIM wireless communication device having two or more RATs concurrently enabled. With respect to a multi-SIM and CRAT wireless communication device, tune-aways (especially long tune-aways) from a first RAT (e.g., LTE) to a second RAT (e.g., GSM) can cause connection release messages associated with the first RAT to be missed. For example, during a tune-away interval to the second RAT, connection release messages (e.g., Over-the-Air (OTA) pages) of the first RAT may not be received given that RF resource of the wireless communication device has been tuned to the second RAT. This may cause a network (e.g., the first network) associated with the first RAT and the wireless communication device to be out of synch. For instance, the first network may set the wireless communication device to be in an idle state (e.g., a Radio Resource Control (RRC)-idle state/mode) in response to sending the connection release message. The wireless communication device, on the other hand, does not have knowledge of the connection release and remains in a connected mode (e.g., a RRC-connected state/mode) as the wireless communication device fails to receive the connection release message. The issue can be more severe in CRAT wireless communication devices due to frequent long tune-aways to the second RAT. Similar scenario may occur in a single-SIM wireless communication device as the single-SIM wireless communication device fails to decode the connection release message due to interference or fading.
Given that the first network sets the wireless communication device to be in the idle mode, the first network may transmit OTA pages to the wireless communication device for a call setup procedure such as, but not limited to, Circuit-Switch Fallback (CSFB) or Voice-over-LTE (VoLTE) procedures. The wireless communication device, upon receiving the OTA page, may ignore the OTA page because the wireless communication device is still set to be in the connected mode, indicating that a call setup is not necessary. This may lead to a dropped call, resulting in negative user experience.